75 GHz InP HBT distributed amplifier with record figures of merit and low power dissipation

We present an InP heterojunction bipolar transistor (HBT) distributed amplifier with a bandwidth of 75 GHz, gain of 14 dB, and a record low power consumption of 78 mW. The HBTs had a 600-nm-thick collector, and hence a relatively low f_T and f_max of 84 and 150 GHz, respectively. The thick collector is a tradeoff required in optoelectronic integrated receivers, in which the PIN diode layers are the same as the base collector layers. To obtain high PIN diode responsivity, the collector layer needs to be thicker than in optimized HBTs. The amplifier topology comprises an emitter follower at the input and a cascode stage, with a resistor and inductance at the emitter follower output, and a peaking line between the HBTs in the cascode stage. The amplifier exhibits matching at the input better than -10 dB up to 85 GHz. The chip contains 16 HBTs and its size is 1.7×0.9 mm².